There are a variety of learning machines in the market, which enable the users to learn a skill or knowledge, such as learning English at home. The conventional learning machine generally comprises a reader and a plurality of cards. Each card has a character, word, symbol or drawing at one side and has a magnetic stripe at the other side. The magnetic stripe is recorded with message corresponding to the symbol at the other side. By inserting a card to a pocket in the learning machine, the message in the card is read by the card reader and broadcast though a speaker. This learning machine provides a boring and inconvenient way of learning, as the user has to keep changing the cards.
There are a lot of software in the market that can be installed in a computer for learning through the computer. However, the cost of a computer and the software are very expensive. To start the software, the user has to turn on the computer and start up the operating system. It is not convenient for a kid to use, and also not able for the kid to carry the computer anywhere as he likes, e.g. from living room to bed room. The sight of the user may be damaged if he views the computer for a long time.
Barcode reader is widely used in the industry for reading a message on a barcode adhered on an object. However, in operation, errors are frequently found, especially when the barcode reader is not closed enough to the barcode for detection. Moreover, it is required to project light on the barcode for the barcode reader to read.
Recently, it is found that radio frequency identification (RFID) techniques have been applied to many applications for easily obtaining messages on an object. The message is stored in a RFID tag and a signal is transmitted wirelessly from the RFID tag to a RFID reader within an effective transmission distance. A large amount of messages can be transmitted by radio frequency identification. It is very simple and convenient to read a message by RFID.
In WO 2006/049374A1, a RFID sensor is disclosed. The RFID sensor comprises a plurality of RFID chips for monitoring different objects e.g. gas valve, door, window and so on. The RFID reader transmits a radio frequency signal to the RFID sensor at a predetermined period, and receives a frequency signal having the unique number of the chosen RFID chip from the RFID sensor. Then the RFID reader transmits the signal to the controller to recognize the used state of the monitored object. The controller can provide the information, e.g. “the gas valve is open”, to the user through a Personal Digital Assistance. The system also comprises a selection unit for choosing the chip by a physical or an electrical operation and connecting the chosen chip to the RFID antenna. Therefore, the accessing of information from the chips is controlled to assure safety.
U.S. Pat. No. 6,486,780 discloses applications for radio frequency identification systems. RFID devices, including handheld RFID devices, and applications may be used in connections with items that are associated with an RFID tag, and optionally a magnetic security element. The devices and applications can be applied for management of books and materials in a library.
A multi-directional RFID antenna is disclosed in U.S. Pat. No. 6,069,564. The antenna provides multi-directional RF communication to a source, such as a RF tag, which comprises a plurality of coils for transmission of RF signals and a switch for selecting at least one of the RF antenna coils for transmission of the RF signal and receipt of the RF response signals whereby the RF signals can be directed toward and received from a plurality of different directions from a fixed position.
It is desired to develop a learning device by applying radio frequency identification such that the learning can be more lively and extensive.